WO2005124911A1

WO2005124911A1 - Electrolyte membrane for solid polymer fuel cell, method for producing same and membrane electrode assembly for solid polymer fuel cell

Info

Publication number: WO2005124911A1
Application number: PCT/JP2005/011466
Authority: WO
Inventors: Eiji Endoh; Shinji Terazono
Original assignee: Asahi Glass Company, Limited
Priority date: 2004-06-22
Filing date: 2005-06-22
Publication date: 2005-12-29
Also published as: JPWO2005124911A1; CA2571138C; EP1772919B2; KR100971640B1; JP3915846B2; US9455465B2; EP1772919B1; KR20070027578A; US8962215B2; US20110262832A1; US20150200412A1; ATE484081T1; CA2571138A1; EP1772919A1; US20070104994A1; DE602005024002D1; EP1772919A4

Abstract

An electrolyte membrane containing cerium ions and composed of a cation-exchange membrane which is made of a polymer compound having a cation-exchange group is used as an electrolyte membrane for solid polymer fuel cells. When the cation-exchange membrane has sulfonic acid groups, cerium ions are preferably contained in an amount of 0.3-20% relative to the -SO3- groups contained in the cation-exchange membrane, and for example, the sulfonic acid groups are ion exchanged with the cerium ions. Consequently, there can be provided an electrolyte membrane for solid polymer fuel cells which enables to generate electricity at high energy efficiency and exhibits high power generation performance regardless of the dew point of a supply gas. This electrolyte membrane for solid polymer fuel cells also enables to stably generate electricity for a long time.

Description

Electrolyte membrane for polymer electrolyte fuel cell, method for producing the same, and membrane electrode assembly for polymer electrolyte fuel cell

Technical field

The present invention relates to an electrolyte membrane for a solid polymer fuel cell capable of obtaining a high output voltage over a long period of time when an initial output voltage is high.

Background art

[0002] A fuel cell is a cell that directly converts the reaction energy of a gas as a raw material into electric energy. A hydrogen-oxygen fuel cell has a reaction product of only water in principle and has a negative effect on the global environment. rare. Above all, polymer electrolyte fuel cells that use solid polymer membranes as electrolytes have developed polymer electrolyte membranes with high ionic conductivity and can operate at room temperature and have high output densities. With increasing social demands for global environmental issues, great expectations are placed on power sources for mobile vehicles such as electric vehicles and small-sized cogeneration systems.

[0003] In a polymer electrolyte fuel cell, a proton-conductive ion exchange membrane is usually used as a solid polymer electrolyte. In particular, an ion exchange membrane made of a perfluorocarbon polymer having a sulfonic acid group is used. Excellent in basic characteristics. In a polymer electrolyte fuel cell, gas-diffusing electrode layers are arranged on both sides of an ion exchange membrane, and a gas containing hydrogen as a fuel and a gas containing oxygen (air or the like) serving as an oxidizing agent are each supplied to an anode. And power to the power sword.

[0004] The reduction reaction of oxygen in the power source of the polymer electrolyte fuel cell is performed by hydrogen peroxide (H 2 O 2).

Since the reaction proceeds via 22, there is a concern that hydrogen peroxide or peroxide radicals generated in the catalyst layer may cause deterioration of the electrolyte membrane. Further, since oxygen molecules permeate the membrane from the force source to the anode, there is a concern that hydrogen peroxide or peroxide radicals may be similarly generated. In particular, when a hydrocarbon-based membrane is used as a solid polymer electrolyte membrane, long-term operation with poor stability against radicals has been a serious problem! [0005] For example, the first practical use of a polymer electrolyte fuel cell was when it was adopted as a power source for a Gemini spacecraft in the United States. It was used as an electrolyte membrane, but had problems with long-term durability. Techniques for solving such problems include a method of adding a transition metal oxide or a compound having a phenolic hydroxyl group capable of catalytically decomposing hydrogen peroxide to a polymer electrolyte membrane (see Patent Document 1). There is known a method of supporting catalytic metal particles in a molecular electrolyte membrane to decompose hydrogen peroxide (see Patent Document 2). However, these techniques are techniques for decomposing the hydrogen peroxide generated, and are not intended to suppress the decomposition of the ion exchange membrane itself. There was a possibility that a serious problem could occur in the durability over the entire period. There was also a problem that the cost would be high o

[0006] On the other hand, an ion exchange membrane which is a perfluorocarbon polymer having a sulfonic acid group has been known as a polymer having much higher stability against radicals than a hydrocarbon polymer. In recent years, polymer electrolyte fuel cells using ion-exchange membranes with these perfluorocarbon polymer powers are expected to be used as power sources in the automotive and residential markets. Is accelerating. In these applications, operation with particularly high efficiency is required, so that operation at higher voltage is desired and at the same time low cost is desired. In addition, low humidification or non-humidification operation is often required due to the efficiency of the entire fuel cell system.

[0007] However, even in a fuel cell using an ion exchange membrane having a sulfonic acid group-containing perfluorocarbon polymer, the stability is extremely high when operating under high humidification, but with low humidification or no humidification. It has been reported that in some operating conditions, voltage degradation is large (see Non-Patent Document 1). That is, under operating conditions with low or no humidification, deterioration of the electrolyte membrane due to hydrogen peroxide or peroxide radicals is considered to occur even in an ion exchange membrane that is a perfluorocarbon polymer having a sulfonic acid group. Conceivable.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-118591 (Claim 1, page 2, lines 2 to 9)

Patent Document 2: JP-A-6-103992 (Means for solving the problem, page 2, 33-37 line)

Non-patent Document 1: New Energy, Sponsored by the National Institute of Advanced Industrial Science and Technology (AIST), 2000 Solid State Fuel Cell R & D Achievement Report, 56 pages, 16-24

Disclosure of the invention

Problems to be solved by the invention

[0009] Accordingly, the present invention is capable of generating electricity with sufficiently high energy efficiency in the practical use of a polymer electrolyte fuel cell for the in-vehicle and residential markets, etc., and enables the humidification temperature (dew point) of the supplied gas. ) Has high power generation performance and is stable for a long period of time both in low humidification operation or low humidification operation below the cell temperature, and in high humidification operation in which humidification is performed at a temperature close to the cell temperature. An object of the present invention is to provide a membrane for a polymer electrolyte fuel cell capable of generating power.

Means for solving the problem

[0010] The present inventors have used an ion-exchange membrane made of a polymer compound having a cation-exchange group, particularly in a fuel cell, in which the membrane is deteriorated under operating conditions with low or no humidification. The present inventors have conducted intensive studies for the purpose of preventing the occurrence of the problem, and have found that the deterioration of the electrolyte membrane can be remarkably suppressed by including a specific ion in the membrane, and have reached the present invention.

[0011] The present invention comprises a polymer compound having a cation exchange group and a cation exchange membrane.

And an electrolyte membrane for a polymer electrolyte fuel cell, characterized by containing cerium ions. The cerium ion is a force capable of taking a +3 or +4 state, and is not particularly limited in the present invention.

[0012] Further, the present invention comprises a cation exchange membrane in which two or more layers of a polymer compound having a cation exchange group and also having a cation exchange group are laminated, and at least one of the two or more layers contains cerium ions. An electrolyte membrane for a polymer electrolyte fuel cell is provided.

[0013] Cerium ions may not exist in any state in the electrolyte membrane as long as they exist as ions, but in one embodiment, some of the cation exchange groups in the cation exchange membrane are formed of cerium ions. Can be present by ion exchange. Therefore, the present invention further provides a polymer compound having a cation-exchange group, comprising a strong cation-exchange membrane, wherein a part of the cation-exchange group is ion-exchanged with cerium ions. High molecular And a cation exchange membrane in which two or more layers composed of a polymer compound having a cation exchange group are laminated, and at least one of the two or more layers is formed of the cation exchange group. An electrolyte membrane for a polymer electrolyte fuel cell, comprising a cation exchange membrane at least partially exchanged with cerium ions.

[0014] The electrolyte membrane of the present invention does not need to contain cerium ions uniformly. A cation exchange membrane (laminated membrane) consisting of two or more layers, in which at least one but not all of the layers is ion-exchanged with cerium ions, that is, cerium ions are not uniformly contained in the thickness direction. It may be. Therefore, especially when it is necessary to increase the durability of the anode side against hydrogen peroxide or peroxide radicals, only the layer closest to the anode should be a layer made of an ion exchange membrane containing cerium ions. You can also.

In the present invention, the polymer compound having a cation exchange group is preferably a polymer compound having a sulfonic acid group.

Further, the present invention provides a method for producing an electrolyte membrane for a polymer electrolyte fuel cell, comprising immersing a cation exchange membrane comprising a polymer compound having a cation exchange group in an aqueous solution containing cerium ions. Provide a method.

[0016] The present invention is also directed to a polymer electrolyte fuel cell comprising an anode and a cathode having a catalyst layer containing a catalyst and an ion exchange resin, and an electrolyte membrane disposed between the anode and the force source. A membrane electrode assembly for a polymer electrolyte fuel cell, wherein the electrolyte membrane is the above-mentioned electrolyte membrane.

[0017] Further, the present invention is for a polymer electrolyte fuel cell comprising an anode and a cathode having a catalyst layer containing a catalyst and an ion exchange resin, and an electrolyte membrane disposed between the anode and the power source. A membrane electrode assembly for a polymer electrolyte fuel cell, wherein the ion exchange resin contained in at least one of the anode and the power source contains cerium ions.

The invention's effect

[0018] The electrolyte membrane of the present invention has excellent resistance to hydrogen peroxide or peroxide radicals. Although the reason for this is not clear, the inclusion of cerium ions in the electrolyte membrane, particularly when some of the cation exchange groups are ion-exchanged by cerium ions, Interaction between the on and the residue from which the proton of the cation exchange group has dissociated (eg,

Three

It is presumed that the resistance of the electrolyte membrane to hydrogen peroxide or hydrogen peroxide is effectively improved.

Since the electrolyte membrane of the present invention has excellent resistance to hydrogen peroxide or peroxide radicals, the polymer electrolyte fuel cell including the membrane electrode assembly having the electrolyte membrane of the present invention Excellent durability and stable power generation over a long period of time.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the polymer compound having a cation exchange group before containing a cerium ion is not particularly limited as long as it has a function of dissociating the cation exchange group to generate a proton. Not done. Specific examples of the cation exchange group include a sulfonic acid group, a sulfonimide group, a phosphonic acid group, a carboxylic acid group, and a ketoimide group. A sulfonic acid group having high acidity and high chemical stability is particularly preferable. Hereinafter, the present invention will be described using a polymer compound having a sulfonic acid group as an example.

[0021] The method for obtaining the electrolyte membrane of the present invention by incorporating cerium ions into a polymer compound having a sulfonic acid group is not particularly limited, and examples thereof include the following methods. (1) A method of immersing a membrane containing a polymer compound having a sulfonic acid group in a solution containing cell ions. (2) A cerium ion-containing salt is added to a dispersion of a polymer compound having a sulfonic acid group by adding a salt containing a cerium ion to the dispersion, or a solution containing a cerium ion and a high- A method in which a dispersion of a molecular compound is mixed to contain cerium ions, and a film is formed using the obtained liquid by a casting method or the like. (3) A method in which an organic metal complex salt of cerium is brought into contact with a cation exchange membrane made of a polymer compound having a sulfonic acid group to contain cerium ions.

It is considered that in the electrolyte membrane obtained by the above method, part of the sulfonic acid groups are ion-exchanged by cerium ions.

[0022] Here, various cerium salts are used in order to obtain a solution containing cerium ions in which cerium ions can be trivalent or tetravalent. + Specific examples of salts containing trivalent cell ions include, for example, cerium acetate (Ce (CH 2 COO)), cerium chloride (CeCl 6.

3 3 2 3 2

), Cerium nitrate (Ce (NO) · 6Η O), cerium sulfate (Ce (SO) · 8Η Ο), Um (Ce (CO) · 8Η O). As salts containing +4 valent cerium ions

2 3 3 2

For example, cerium sulfate (Ce (SO 3) 4Η0), diammonium nitrate (Ce (NH

4 2 2 4

) (NO)), tetraammonium cerium sulfate (Ce (NH) (SO) · 4 O)

2 3 6 4 4 4 4 2

The Cerium acetyl acetate (Ce (CH 2 CO 3)

Three

CHCOCH) · 3Η Ο). Especially, cerium nitrate and cerium sulfate

3 3 2

It is preferable because it is water-soluble and easy to handle. Further, nitric acid or sulfuric acid generated when ion exchange of a polymer compound having a sulfonic acid group with these aqueous solutions is preferable because it can be easily dissolved in the aqueous solution and removed.

For example, when the cerium ion is trivalent, when the sulfonic acid group is ion-exchanged by the cerium ion, Ce ³⁺ bonds to three —SOs as shown below.

[0024] [Formula 1]

^S 0 ₃

In the present invention, the number of cerium ions contained in the electrolyte membrane is

It is preferable that the number of (3) is 0.3 to 20% (hereinafter, this ratio is referred to as “cerium ion content”). O When the cerium ion has the above structure completely, the cerium ion This is equivalent to 0.9 to 60% of the total amount of the sulfonic acid groups ion-exchanged with cerium ions (hereinafter, this ratio is referred to as “replacement”). Rate). The cerium ion content is more preferably 0.7 to 16%, further preferably 1 to 13%, further preferably 1.5 to 12%, and still more preferably 2 to 10%. In terms of the above replacement ratio, 1 to 60% is more preferable, 2 to 50% is still more preferable, 3 to 40% is still more preferable, and 5 to 30% is further preferable.

[0026] If the content of cerium ions is smaller than the above range, there is a possibility that sufficient stability to hydrogen peroxide or radical peroxide may not be ensured. If the cerium ion content is larger than the above range, sufficient conductivity of hydrogen ions cannot be secured. In addition, the film resistance may be increased and the power generation characteristics may be reduced.

[0027] When the electrolyte membrane of the present invention is composed of a laminated membrane, the total electrolyte membrane is based on one SO- group.

The cerium ion content of the layer containing cerium ions may be higher than the above range as long as the ratio of cerium ions to 3 is within the above range. In addition, as a method for manufacturing a laminated film, for example, a cation exchange membrane containing cerium ions is prepared by any of the above methods (1) to (3), and a cation exchange membrane containing no cerium ions is prepared. Although it is preferable to produce through a step of laminating with, it is not particularly limited.

[0028] In addition, when the content of cerium ions is preferably represented by a ratio based on the mass of the electrolyte membrane, the content of cerium is preferably 0.02 to 8% with respect to the mass of the entire electrolyte membrane. Further, the power is preferably 0.05 to 6.6%, more preferably 0.07 to 5.3%.

In the present invention, the polymer compound having a sulfonic acid group before containing cerium ions is not particularly limited, but has an ion exchange capacity of 0.5 to 3.0 meq. More preferably, it is 0.7 to 2.5 meq. Zg dry resin is more preferable. It is particularly preferable that it is 1.0 to 2.5 meq. Zg dry fat. If the ion exchange capacity is too low, sufficient conductivity of hydrogen ions cannot be secured when the sulfonic acid groups are ion-exchanged with cerium ions, which may increase the membrane resistance and lower the power generation characteristics. If the ion exchange capacity is too high, the water resistance and strength of the membrane may decrease. In addition, it is preferable that the polymer compound is a fluoropolymer, particularly a perfluorocarbon polymer having a sulfonate group (V, including an ether bond oxygen atom, etc.). Also,) is preferred. The perfluorocarbon polymer is not particularly limited. However, the perfluorocarbon represented by CF = CF- (OCF CFX) —O— (CF) —SOH

2 2 m p 2 n 3

A polymerized unit based on a compound (m represents an integer of 0 to 3, n represents an integer of 1 to 12, p represents 0 or 1, and X represents a fluorine atom or a trifluoromethyl group); It is preferably a copolymer containing a polymerized unit based on tetrafluoroethylene.

[0030] Preferable examples of the above-mentioned perfluorovinylide conjugate include, more specifically, compounds represented by the following formulas (i) to (iii). In the following formula, q represents an integer of 1 to 8, r represents an integer of 1 to 8, and t represents an integer of 1 to 3.

Equation 1 ^{_{[0031] CF 2 = CFO (}} CF 2) q - S0 3 H (i)

_{_{CF 2 = CFOCF 2 CF (CF}} 3) O (CF 2) r _S0 3 H ... (ii)

CF ₂ = CF (OCF ₂ CF (CF ₃ )) _t O (CF ₂ ) ₂ — S〇 ₃ H… (iii)

[0032] When a perfluorocarbon polymer having a sulfonic acid group is used, a polymer obtained by fluorinating after polymerization to have the terminal of the polymer fluorinated may be used. When the terminal of the polymer is fluorinated, the stability to hydrogen peroxide and radicals is further improved, so that the durability is improved.

Further, as the polymer compound having a sulfonic acid group before containing a cerium ion, a compound other than a perfluorocarbon polymer having a sulfonic acid group can be used. For example, a polymer compound having a structure in which a polymer has an aromatic ring in a main chain or in a main chain and a side chain, and a sulfonic acid group is introduced into the aromatic ring, and has an ion exchange capacity of 0. High molecular compounds that are 8 to 3.0 milliequivalents Zg dry resin can be preferably used. Specifically, for example, the following polymer compounds can be used.

[0034] Sulfonated polyarylene, sulfonated polybenzozoazole, sulfonated polybenzothiazole, sulfonated polybenzoimidazole, sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polyphenylene Lensenolefon, Snollefonidani Polyphenylene Sulfide, Snorrefonidani Polyphenylene Sulfoxide, sulfonated polyphenylene-sulfide, sulfonated polyphenylenesulfide, sulfonated polyether ketone, sulfonated polyetheretherketone, sulfonated polyetherketoneketone , Sulfonated polyimide and the like.

The polymer electrolyte fuel cell having the electrolyte membrane of the present invention has, for example, the following configuration. That is, the electrolyte membrane of the present invention is provided with a membrane electrode assembly in which an anode having a catalyst layer containing a catalyst and an ion exchange resin and a force sword are arranged on both surfaces. The anode and the force source of the membrane electrode assembly are preferably provided with a gas diffusion layer made of carbon such as carbon cloth or carbon paper outside the catalyst layer (the side opposite to the membrane). On both sides of the membrane / electrode assembly, separators having grooves formed therein for passage of fuel gas or oxidizing gas are arranged. Then, a stack in which a plurality of membrane electrode assemblies are stacked via a separator is configured, and hydrogen gas is supplied to the anode side, and oxygen or air is supplied to the force source side. It is. At the anode, the reaction H → 2H ⁺ + 2e—

2

/ 2 + 2H ⁺ + 2e "→ HO reaction occurs, converting chemical energy to electrical energy

twenty two

Is converted.

Further, the electrolyte membrane of the present invention can be used for a direct methanol fuel cell that supplies methanol instead of fuel gas to the anode side.

[0036] The above-mentioned catalyst layer is obtained according to a usual method, for example, as follows. First, a solution of a conductive carbon black powder carrying fine particles of a platinum catalyst or platinum alloy catalyst and a solution of a perfluorocarbon polymer having a sulfonate group are mixed to obtain a uniform dispersion. A gas diffusion electrode is formed by such a method to obtain a membrane electrode assembly.

[0037] The first method is a method in which the above-mentioned dispersion liquid is applied to both sides of an electrolyte membrane, dried, and then both sides are brought into close contact with two carbon cloths or carbon paper. In the second method, the dispersion is applied to two sheets of carbon cloth or carbon paper and dried, and then sandwiched from both sides of the ion exchange membrane so that the surface to which the dispersion is applied is in close contact with the ion exchange membrane. This is the method of incorporation. Here, the carbon cloth or carbon paper has a function as a gas diffusion layer and a function as a current collector for uniformly diffusing the gas into the layer containing the catalyst. Also, a method of applying the above-mentioned dispersion liquid to a separately prepared base material to form a catalyst layer, bonding it to an electrolyte membrane by a method such as transfer, peeling the base material, and sandwiching the base material with the gas diffusion layer. Can also be used.

[0038] The ion exchange resin contained in the catalyst layer is not particularly limited, but is preferably a polymer compound having a sulfonic acid group, and is preferably a perfluorocarbon polymer having a sulfonic acid group. More preferably, there is. The ion exchange resin in the catalyst layer may contain cerium ions as in the case of the electrolyte membrane of the present invention. Ion-exchange resin containing cerium ions can be used for both anode and power source, and decomposition of resin is effectively suppressed.

In addition, the polymer electrolyte fuel cell is further provided with durability. In addition, an ion exchange resin containing no cell ions can be used as the electrolyte membrane, and only the ion exchange resin in the catalyst layer can contain cell ions.

In the case where both the ion exchange resin and the electrolyte membrane in the catalyst layer contain cerium ions! / ヽ, for example, a joined body of the catalyst layer and the electrolyte membrane is prepared in advance, and the joined body is made of cerium. It can also be produced by immersion in a solution containing cations. When cerium ions are contained in the catalyst layer, the catalyst layer is formed by the above-described method as a coating liquid obtained by dispersing the catalyst in a dispersion containing a polymer compound having a sulfonic acid group and cerium ions. It is also possible. In this case, only one of the force sword and the anode may contain cerium ions, and both the force sword and the anode may contain cerium ions. At this time, it is also possible to use a dispersion having different contents of cerium ions between the force sword and the anode, and to adjust the contents of the force sword and the anode so that the cerium ions have different contents. In particular the anode contained in the polymer compound having a sulfonic acid group - it contains cerium ions 10-30 mole ^_0/0 SO- group, the force Sword 3-10 mol

Three

When cerium ions are contained in an amount of 0.1%, decomposition of the ion exchange resin in the catalyst layer can be effectively suppressed, and therefore, it is more preferable from the viewpoint of improving durability.

[0040] The electrolyte membrane of the present invention may be a membrane in which only a polymer compound having a sulfonic acid group and partially containing cerium ions is strong, but it may be polytetrafluoroethylene or polytetrafluoroethylene which may contain other components. The membrane may be reinforced with fibers of other resin such as perfluoroalkyl ether, woven fabric, non-woven fabric, porous body and the like. Even in the case of a reinforced membrane, the electrolyte membrane of the present invention can be obtained by immersing a cation exchange membrane having a reinforced sulfonic acid group in a solution containing cerium ions. Further, a method of forming a film using a dispersion liquid containing a polymer compound ion-exchanged with cerium ions can also be applied. When the electrolyte membrane is reinforced, the whole membrane may be reinforced, but the periphery of the membrane may be reinforced in a frame shape with a film, a sheet, or the like. If the film is reinforced in a frame shape, the strength of the peripheral part will increase and the handling will be improved. The entire membrane may be reinforced with a high porosity! Reinforcing material and the porosity may be low only at the periphery, or may be reinforced with a reinforcing material without voids.

The polymer electrolyte fuel cell provided with the membrane / electrode assembly of the present invention has excellent durability even at a high temperature, and therefore can be operated at 100 ° C. or more to generate power. When hydrogen obtained by reforming methanol, natural gas, gasoline, or the like is used as a fuel gas, even if a trace amount of carbon monoxide is contained, the electrode catalyst is poisoned and the output of the fuel cell is liable to decrease. If the operating temperature is set to 100 ° C or more, it is possible to suppress poisoning. When the operating temperature is set to 120 ° C or more, the effect of suppressing the more favorable poisoning becomes higher. Example

Hereinafter, the present invention will be specifically described with reference to Examples (Examples 1 to 5, 10, 12 to 15) and Comparative Examples (Examples 6 to 9, 1

Although the description will be made using 1), the present invention is not limited to these.

[0043] [Example 1]

As a solid polymer electrolyte membrane, a perfluorocarbon polymer having sulfonic acid groups A 50 m thick ion exchange membrane (trade name: Flemion, manufactured by Asahi Glass Co., Ltd., ion exchange capacity: 1.1 meq. Zg drying) (Fat) and a size of 5 cm × 5 cm (area 25 cm ² ) was used. The weight of the whole film was left in dry nitrogen for 16 hours and then measured in dry nitrogen to find that it was 0.251 g. The amount of sulfonic acid groups in this membrane is determined by the following equation. 0.25 (g) XI. 1 (meq. Zg dry resin) = 0.276 (meq.).

Next, cerium nitrate (Ce (NO 2) · 6Η0) 12.Omg was added so as to contain cerium ions (+3 valences) corresponding to 30% (equivalent) of the amount of sulfonic acid groups in the membrane. To 500 mL of distilled water

3 3 2

After dissolving, the above-mentioned ion exchange membrane was immersed in the mixture and stirred at room temperature for 40 hours with a stirrer so that cerium ions were contained in the ion exchange membrane. The cerium nitrate solution before and after the immersion was analyzed by inductively coupled plasma (ICP) emission spectroscopy. As a result, the content of cerium ions in this ion exchange membrane (the ratio of cerium ions to the number of SO— groups in the membrane)

Three

Was found to be 9.3%.

Next, a catalyst powder (manufactured by N-Chemcat Co., Ltd.) in which platinum was supported on a carbon carrier (specific surface area 800 m ² Zg) so as to contain 50% of the total mass of the catalyst 1. lg was mixed. CF = CF / CF = CFOCF CF (CF) 0 (CF) SO H

5.6 g of a liquid having a solid content of 9% by mass in which a 2 2 2 3 2 2 3 combination (ion exchange capacity l. 1 meq. Zg dried resin) was dispersed in ethanol was mixed. This mixture was mixed and pulverized using a homogenizer (trade name: Polytron, manufactured by Kinemachi Riki Co., Ltd.) to prepare a coating liquid for forming a catalyst layer.

[0046] The coating solution was applied on a polypropylene base film using a bar coater, and then dried in a dryer at 80 ° C for 30 minutes to prepare a catalyst layer. The amount of platinum per unit area contained in the catalyst layer was calculated by measuring the mass of the base film alone before the formation of the catalyst layer and the mass of the base film after the formation of the catalyst layer. ^{It was 2} o Next, the above-mentioned ion-exchange membrane containing cerium ions was used, and the catalyst layers formed on the base film were arranged on both sides of the membrane, and were transferred by hot pressing to remove the anode catalyst. A membrane catalyst layer assembly in which the catalyst layer and the force sword catalyst layer were bonded to both sides of the ion exchange membrane, respectively, was obtained. The electrode area was 16 cm ² .

[0048] A membrane electrode assembly was prepared by sandwiching the membrane catalyst layer assembly between two gas diffusion layers having a thickness of 350 µm and having a carbon cloth force, and this was assembled into a power generation cell and opened as an acceleration test. A circuit test (OCV test) was performed. Tests, at atmospheric pressure, current density 0. 2AZcm ² to correspond to that of hydrogen (utilization ratio 70%) and subjected supply air (% utilization 40) to the anode and force cathode, respectively, the cell temperature 90 ° C, The anode gas had a dew point of 60 ° C and the power source gas had a dew point of 60 ° C. Operation was performed for 100 hours in an open circuit state without power generation, and the voltage change during that time was measured. Before and after the test, hydrogen was supplied to the anode and nitrogen was supplied to the power source, and the amount of hydrogen gas leaking from the anode to the power source through the membrane was analyzed to determine the degree of membrane degradation. Table 1 shows the results.

Next, a membrane electrode assembly was produced in the same manner as described above, incorporated into a power generation cell, and subjected to a durability test under low humidification operating conditions. The test conditions were as follows: At normal pressure, hydrogen (utilization rate 70%), Z air (utilization rate 40%) was supplied, and at a cell temperature of 80 ° C, the current density was 0.2 AZcm ²の. Initial characteristic evaluation and durability evaluation were performed. Hydrogen and air were humidified and supplied into the cell at a dew point of 80 ° C on the anode side and a dew point of 50 ° C on the power source side. The relationship was measured. Table 2 shows the results. In addition, the relationship between the cell voltage at the initial stage of operation, the elapsed time after the start of operation, and the cell voltage was measured in the same manner except that the dew point on the force side was changed to 80 ° C under the above-described cell evaluation conditions. Table 3 shows the evaluation results.

[0050] [Example 2]

Instead of using the cerium nitrate aqueous solution used in Example 1, 9.8 mg of cerium sulfate containing cerium ion (+ trivalent) dissolved in 500 mL of distilled water was used.

2 4 3 2

Other than that, the same commercially available ion exchange membrane as used in Example 1 is treated in the same manner as in Example 1 to obtain a membrane having a cerium ion content of 9.3%. Next, a membrane catalyst layer assembly is obtained using this membrane in the same manner as in Example 1, and further a membrane electrode assembly is obtained. About this membrane electrode assembly When the same evaluation as in Example 1 is performed, the results shown in Tables 1 to 3 are obtained.

[Example 3]

Instead of the cerium nitrate aqueous solution used in Example 1, cerium nitrate (Ce (NO) 6Η0) 8.

3 3 2

Except that an aqueous solution of Omg dissolved in 500 mL of distilled water was used, the same treatment as in Example 1 was performed using the same commercially available ion-exchange membrane as in Example 1, and the cerium ion content was determined. Gave a 6.3% membrane. Next, a membrane catalyst layer assembly was obtained using this membrane in the same manner as in Example 1, and a membrane electrode assembly was obtained. The same evaluation as in Example 1 was performed for this membrane / electrode assembly, and the results are shown in Tables 1 to 3.

[0052] [Example 4]

Instead of the cerium nitrate aqueous solution used in Example 1, cerium nitrate (Ce (NO) 6Η0) 4.

3 3 2

Except that an aqueous solution of Omg dissolved in 500 mL of distilled water was used, the same treatment as in Example 1 was performed using the same commercially available ion-exchange membrane as in Example 1, and the cerium ion content was determined. Get 3.3% membrane. Next, a membrane catalyst layer assembly is obtained using this membrane in the same manner as in Example 1, and further a membrane electrode assembly is obtained. When the same evaluation as in Example 1 is performed on this membrane / electrode assembly, the results shown in Tables 1 to 3 are obtained.

[0053] [Example 5]

As a solid polymer electrolyte membrane, a 50-m-thick ion-exchange membrane formed of a polyetheretherketone having a sulfonic acid group and having a part of the sulfonic acid groups ion-exchanged with cerium ions as follows. Produced. That is, 60 g of granular commercially available polyester ether ketone (PEEK-450P, manufactured by Victrex, UK) is added little by little to 1200 g of 98% sulfuric acid at room temperature, and stirred at room temperature for 60 hours to obtain a uniform solution. Thus, a solution of a polymer compound having sulfonic acid groups introduced into polyetheretherketone was obtained. Next, while cooling the solution, the solution was dropwise added to 5 L of distilled water to precipitate polyether ether ketone having a sulfonic acid group, which was separated by filtration. Then, this was washed with distilled water until neutral, and then dried under vacuum at 80 ° C. for 24 hours to obtain 48 g of polyetheretherketone having a sulfonate group.

Next, after accurately weighing about lg of this compound, it is immersed in 500 mL of a 1N aqueous sodium chloride solution and reacted at 60 ° C. for 24 hours to remove protons of sulfonic acid groups and sodium ions. Replaced on. After cooling the sample to room temperature, it is washed thoroughly with distilled water, and the ion-exchange capacity is determined by titrating the ion-exchanged aqueous sodium chloride solution and the washed distilled water with 0.01 N sodium hydroxide. I asked. The ion exchange capacity was 1.6 meq Zg dried resin.o

Next, this polyetheretherketone having a sulfonic acid group is dissolved in N-methyl-2-pyrrolidone (NMP) to form a solution of about 10% by mass, and this is a substrate having a polytetrafluoroethylene power at room temperature. After casting, a film having a thickness of 50 m was obtained by drying at 100 ° C. for 10 hours in a nitrogen atmosphere to evaporate NMP. Next, this film was cut into a size of 5 cm × 5 cm (area 25 cm ² ), and the weight of the whole film was measured in the same manner as in Example 1 to find that it was 0.168 g. The amount of sulfonic acid groups in this membrane is determined by the following equation.

0. 168 (g) X I. 6 (meq. Zg dried resin) = 0.269 (meq.).

[0056] Cerium nitrate (Ce (NO) · 6Η0) containing Ce ion (+ trivalent) corresponding to an amount (equivalent) of about 30% of the amount of sulfonic acid groups of this membrane. Aqueous solution dissolved in water

3 3 2

Then, the above-mentioned ion exchange membrane is immersed in the solution and stirred at room temperature for 40 hours using a stirrer to obtain a membrane having a cerium ion content of 10.3%. Next, a membrane catalyst layer assembly is obtained using this membrane in the same manner as in Example 1, and a membrane electrode assembly is further obtained. When the same evaluation as in Example 1 is performed for this membrane / electrode assembly, the results shown in Tables 1 to 3 are obtained.

[0057] [Example 6]

As a solid polymer electrolyte membrane, the same commercially available ion exchange membrane as used in Example 1 was used without any treatment, and then the membrane catalyst layer assembly was used in the same manner as in Example 1 using this membrane. Thus, a membrane electrode assembly was obtained. When the same evaluation as in Example 1 was performed for this membrane / electrode assembly, the results shown in Tables 1 to 3 were obtained.

[0058] [Example 7]

In the same manner as in Example 1, the same commercially available ion-exchange membrane as that used in Example 1 was replaced with 9.8 mg of calcium nitrate (Ca (NO) 4Η0) containing calcium ions (+2) in 500 mL of distilled water. Dissolved in

3 2 2

It is immersed in the dissociated aqueous solution to obtain a film having a calcium ion content of 10.3%. Next, a membrane catalyst layer assembly is obtained using this membrane in the same manner as in Example 1, and further a membrane electrode assembly is obtained. When this membrane electrode assembly was evaluated in the same manner as in Example 1, the results shown in Tables 1 to 3 were obtained. The

[0059] [Example 8]

In the same manner as in Example 1, the same commercially available ion-exchange membrane as used in Example 1 was obtained by dissolving 10.3 mg of copper sulfate (CuSO.5ΗO) containing copper ions (+2) in 500 mL of distilled water. To

4 2

After immersion, a film with a copper ion content of 9.7% is obtained. Next, a membrane catalyst layer assembly is obtained using this membrane in the same manner as in Example 1, and further a membrane electrode assembly is obtained. When the same evaluation as in Example 1 is performed on this membrane / electrode assembly, the results shown in Tables 1 to 3 are obtained.

[0060] [Example 9]

A membrane catalyst layer assembly was obtained in the same manner as in Example 5 except that the ion exchange membrane having a sulfonic acid group-containing polyetheretherketone force obtained in Example 5 was used without being treated with cerium ions. Obtain an electrode assembly. When this membrane electrode assembly is evaluated in the same manner as in Example 1, the results shown in Tables 1 to 3 are obtained.

[0061] [Example 10]

Instead of the cerium nitrate aqueous solution used in Example 1, cerium nitrate (Ce (NO) 6Η0) 6.

3 3 2

Except that an aqueous solution of Omg dissolved in 500 mL of distilled water was used, the same treatment as in Example 1 was performed using the same commercially available ion-exchange membrane as in Example 1, and the cerium ion content was determined. Gave a 4.7% membrane. Next, a membrane catalyst layer assembly was obtained in the same manner as in Example 1 using this membrane.

[0062] This membrane catalyst layer assembly was sandwiched between two gas diffusion layers having a thickness of 350 µm and also having a carbon cloth force to produce a membrane electrode assembly, which was incorporated into a power generation cell. An endurance test was carried out under operating conditions of 120 ° C and moisture. The anode, the force cathode both pressurized to 200 kPa, hydrogen (utilization ratio 50%) Z supplying air (utilization ratio 50%), a solid polymer fuel cell at a current density of 0. 2AZcm ² to have you in the cell temperature 120 ° C The initial property evaluation and durability evaluation were performed. The anode side has a dew point of 100 ° C, and the power source side has a dew point of 100 ° C.Hydrogen and air are humidified and supplied into the cell, respectively. The relationship was measured. Table 4 shows the results.

[0063] [Example 11]

The same commercially available ion exchange membrane as used in Example 1 was used as the solid polymer electrolyte membrane. Next, a membrane catalyst layer assembly was obtained using this membrane in the same manner as in Example 1 to obtain a membrane electrode assembly. When the same evaluation as in Example 10 was performed for this membrane / electrode assembly, the power generation voltage rapidly dropped to about 0 V after 110 hours, and power generation was disabled. After the test, the film was taken out and examined. As a result, it was found that a large hole was formed in the film, which caused the sudden voltage drop.

[Preparation of solution of perfluorocarbon polymer having sulfonic acid group]

CF = CF / CF = CFOCF CF (CF) 0 (CF) SO H copolymer (ion exchange capacity

2 2 2 2 3 2 2 3

300 g, 420 g of ethanol and 280 g of water were charged into a 2 L-year-old autoclave, sealed, mixed and stirred with a double helical blade at 105 ° C for 6 hours to obtain a uniform liquid. (Hereinafter referred to as solution A). Solution A had a solid content concentration of 30% by mass.

[Preparation of solution of perfluorocarbon polymer having sulfonic acid group containing cerium ion]

In a 300 mL glass round bottom flask, 100 g of solution A and cerium carbonate hydrate (Ce (CO

twenty three

) · 8 を O) with 1.OOg to make a polytetrafluoroethylene (PTFE) meniscus wing

3 2

And stirred at room temperature for 8 hours. Force generated by CO generation from the start of stirring Final

2

, A uniform transparent liquid composition (hereinafter referred to as solution B) was obtained. The solid concentration of the solution B was 30.2% by mass.

[0066] The cerium ion content of this solution B was examined as follows. Solution B was cast-coated on a 100 μm ethylene-tetrafluoroethylene copolymer (ETFE) sheet (trade name: Aflex 100 N, manufactured by Asahi Glass Co., Ltd.) using a die coater, and then at 80 ° C for 10 minutes. 120 after pre-drying. Dried for 10 minutes at C, then 150 C, annealing was performed for 30 minutes to obtain an electrolyte membrane having a thickness of 50 m. A 5 cm X 5 cm membrane was cut out of this electrolyte membrane, left in dry nitrogen for 16 hours, weighed accurately, and impregnated in 0.1N HC1 aqueous solution to completely remove cerium ions. An extracted liquid was obtained. The cerium in the electrolyte membrane was quantified by measuring this solution by ICP emission spectrometry. The amount of cerium ions was 1.5% based on the mass of the membrane, and the content of cerium ions was perfluorinated. Number of SO— groups in carbon polymer

10% compared to 3.

[0067] [Example 12] The solution A was cast-coated on a 100 m ETFE sheet using a die coater, pre-dried at 80 ° C for 10 minutes, dried at 120 ° C for 10 minutes, and further dried at 150 ° C for 30 minutes. To obtain a 25 m-thick electrolyte membrane. Similarly, the above solution B was cast-coated on a 100 / zm ETFE sheet with a die coater, pre-dried at 80 ° C for 10 minutes, dried at 120 ° C for 10 minutes, and further dried at 150 ° C. Then, annealing is performed for 30 minutes to obtain a 25 m-thick electrolyte membrane having a cerium ion content of 10%. Next, these membranes are hot-pressed at 150 ° C to obtain a composite membrane of a solid polymer electrolyte having a film thickness in which the cerium ion content is uneven in the thickness direction.

Next, a catalyst powder (manufactured by N-Chemcat Co., Ltd.) in which platinum is supported on a carbon carrier (specific surface area: 800 m ² Zg) so as to contain 50% of the total mass of the catalyst. mix lg. To this mixed solution, 5.6 g of a solution obtained by diluting the above solution A with ethanol to a solid content concentration of 9% by mass is mixed. This mixture is mixed and pulverized using a homogenizer to prepare a coating solution for forming a catalyst layer.

[0069] This coating solution is applied on a polypropylene base film using a bar coater, and then dried in an oven at 80 ° C for 30 minutes to prepare a catalyst layer. By measuring the mass of the substrate film after the mass and the catalyst layer formed of only the base film before forming the catalyst layer, calculating the amount of platinum per unit area contained in the catalyst layer, 0. 5mgZcm ² It is.

Next, using the above-mentioned composite membrane, containing cerium ions, a catalyst layer formed on the above-mentioned base film was disposed as an anode on the membrane surface, and containing cerium ions. On the other hand, the catalyst layer formed on the above-mentioned base film is arranged as a force sword on the membrane surface, and is transferred by a hot press method so that the anode catalyst layer and the force sword catalyst layer are formed on both surfaces of the ion exchange membrane. A bonded membrane catalyst layer assembly is obtained. Note that the electrode area is 16 cm ² . A membrane electrode assembly is further obtained from this membrane catalyst layer assembly in the same manner as in Example 1. When the same open circuit test as in Example 1 is performed on this membrane / electrode assembly, the results are as shown in Table 1.

Next, a membrane electrode assembly is prepared and assembled into a power generation cell in the same manner as described above, and a durability test is performed under the same low humidification and high temperature operation conditions as in Example 10. That pressurized to the anode and cathode Dotomo 200 kPa, the hydrogen supply (utilization ratio 50%) Z Air (50% utilization), a polymer electrolyte fuel cell at a current density of 0. 2AZcm ² in the cell temperature 120 ° C Early features Carry out the performance evaluation and durability evaluation. The anode side has a dew point of 100 ° C and the power side has a dew point of 10o ° c.Hydrogen and air are humidified and supplied into the cell, respectively. Is measured. Table 4 shows the results.

Next, a membrane / electrode assembly is prepared and assembled into a power generation cell in the same manner as described above, and a durability test is performed under the same high humidification operating conditions as in Example 1. That test conditions, under atmospheric pressure, hydrogen was supplied (utilization 70%) Z Air (40% utilization), the polymer electrolyte fuel cell at a current density of 0. 2AZcm ² at a cell temperature of 80 ° C Initial Conduct property evaluation and durability evaluation. A dew point of 80 ° C was applied to the anode and a dew point of 80 ° C was applied to the power source.Hydrogen and air were humidified and supplied into the cell. Measure. Table 3 shows the results.

[Example 13]

The solution A was cast-coated on a 100 m ETFE sheet using a die coater, pre-dried at 80 ° C for 10 minutes, dried at 120 ° C for 10 minutes, and further dried at 150 ° C for 30 minutes. To obtain an electrolyte membrane having a thickness of 50 / 50πι and a size of 5 cm × 5 cm.

Next, a catalyst powder (manufactured by N-Chemcat Co., Ltd.) in which platinum was supported on a carbon carrier (specific surface area: 800 m ² Zg) so as to contain 50% of the total mass of the catalyst. lg was mixed. To this mixed solution, 5.6 g of a solution obtained by diluting the above solution B with ethanol to a solid content concentration of 9% by mass was mixed. This mixture was mixed and pulverized using a homogenizer to prepare a coating liquid for forming an anode catalyst layer.

[0075] This coating solution was applied on a polypropylene base film using a bar coater, and then dried in a dryer at 80 ° C for 30 minutes to remove the perfluorocarbon weight in the catalyst layer. included in the combined - SO- prepare an anode catalyst layer containing the cerium ions of 10 mole ^_0/0 groups

Three

It was. The amount of platinum per unit area contained in the catalyst layer was calculated by measuring the mass of only the base film before forming the catalyst layer and the mass of the base film after forming the catalyst layer. 5mgz cm Shiatsu 7

On the other hand, except that the solution A was used instead of the solution B, a sword catalyst layer containing no cerium was prepared in the same manner as the anode catalyst layer.

Next, on both sides of the electrolyte membrane prepared using the solution A, The anode layer and the force catalyst layer are placed, and the catalyst layer is transferred to the membrane by the hot press method. The SO 2 contained in the perfluorocarbon polymer in the catalyst layer

An anode catalyst layer containing the cerium ions of 10 mole ^_0/0 of 3 groups, the containing cerium ions it!ヽcathode catalyst layer bonded on both surfaces of the polymer electrolyte membrane to obtain a membrane-catalyst layer assembly . The electrode area was 16 cm ² .

A membrane / electrode assembly was further obtained from this membrane / catalyst layer assembly in the same manner as in Example 1. An open circuit test similar to that of Example 1 was performed on this membrane electrode assembly. The results are shown in Table 1. In addition, a membrane electrode assembly similar to the above was fabricated and assembled into a power generation cell, and a durability test was performed under the same low-humidification and high-humidification operating conditions as in Example 1 to obtain the results shown in Tables 2 and 3. It becomes.

[0078] [Example 14]

The amount of cerium carbonate hydrate (Ce (CO) · 8Η において) was adjusted to 2.

2 3 3 2

A solution having a cerium ion content of 20% with respect to the number of —SO— groups contained in the perfluorocarbon polymer was obtained in the same manner except that the amount was changed to 00 g. Next, apply this solution to the anode

Three

Except for using the catalyst layer, the same procedure as in Example 13 was carried out to obtain an anode electrode containing cerium ions containing 20 mol% of SO— groups contained in the perfluorocarbon polymer in the catalyst layer.

Three

A membrane catalyst layer assembly was obtained in which a medium layer and a force sword catalyst layer containing no cerium ions were bonded to both surfaces of the polymer electrolyte membrane.

[0079] From this membrane catalyst layer assembly, a membrane electrode assembly was further obtained in the same manner as in Example 1. An open circuit test similar to that of Example 1 was performed on this membrane electrode assembly. The results are shown in Table 1. In addition, a membrane electrode assembly similar to the above was fabricated and assembled into a power generation cell, and a durability test was performed under the same low-humidification and high-humidification operating conditions as in Example 1 to obtain the results shown in Tables 2 and 3. It becomes.

[0080] [Example 15]

In Example 13, a membrane catalyst layer assembly was obtained in the same manner as in Example 13, except that the solution A was used to form an anode catalyst layer without containing cerium ions. The membrane / catalyst layer assembly is immersed in an aqueous solution of cerium nitrate (Ce (NO).

3 3 2

A membrane catalyst layer assembly was obtained in which a part of the sulfonic acid groups of the fluorocarbon polymer was ion-exchanged with cerium ions. Ion exchange was performed by the following method.

First, the weight of the entire film produced by the cast film formation was left to stand in dry nitrogen for 16 hours. After that, it was 0.25 lg when measured in dry nitrogen. The amount of sulfonic acid groups in this membrane is determined by the following equation.

0.251 (g) X I. 1 (meq. Zg dry resin) = 0.276 (meq.).

Next, cerium nitrate (Ce (NO 2) · 6Η) was added so as to contain a number of cerium ions (+3) corresponding to 10% of the number of sulfonic acid groups in the membrane portion of the membrane catalyst layer assembly. 0) 12.Omg 5

3 3 2

Dissolved in OO mL of distilled water. The membrane catalyst layer assembly was immersed in the mixture, and stirred at room temperature for 40 hours using a stirrer to partially remove the sulfonic acid groups of the perfluorocarbon polymer in the membrane catalyst layer assembly. Cerium ions were contained in the entire membrane catalyst layer assembly by ion exchange with the ions. The cerium nitrate solution before and after immersion was analyzed by ICP emission spectroscopy. As a result, the membrane catalyst layer assembly showed a cerium ion equivalent to 9.3% of the number of —SO— groups in the membrane part of the membrane catalyst layer assembly. Was found to be contained.

[0083] In the same manner as in Example 1 of the membrane catalyst layer assembly, a membrane electrode assembly was further obtained. An open circuit test similar to that of Example 1 was performed on this membrane electrode assembly. The results are shown in Table 1. In addition, a membrane electrode assembly similar to the above was fabricated and assembled into a power generation cell, and a durability test was performed under the same low-humidification and high-humidification operating conditions as in Example 1 to obtain the results shown in Tables 2 and 3. It becomes.

[Table 1]

[0085] [Table 2] Initial output durability Z output voltage (V)

Voltage (V) After 500 hours After 2000 hours

Example 1 0.77 0.77 0.76

Example 2 0.77 0.76 0.76

Example 3 0.76 0.75 0.75

Example 4 0.76 0.75 0.74

Example 5 0.75 0.73 0.72

Example 6 0.77 0.70 0.65

Example 7 0.75 0.66 0.60

Example 8 0.75 0.62 0.55

Example 9 0.73 0.58 0.50

Example 1 3 0.77 0.76 0.75

Example 1 4 0.77 0.76 0.76

Example 1 5 0.75 0.74 0.73

S3] Initial output durability Output voltage (V)

Voltage (V) After 500 hours After 2000 hours

Example 1 0.78 0.78 0.78

Example 2 0.78 0.78 0.77

Example 3 0.78 0.77 0.77

Example 4 0.78 0.77 0.77

Example 5 0.76 0.75 0.74

Example 6 0.77 0.73 0.70

Example 7 0.76 0.7 0.7 1 0.67

Example 8 0.76 0.70 0.64

Example 9 0.74 0.65 0.60

Example 1 2 0.78 0.77 0.76

Example 1 3 0.78 0.77 0.76

Example 1 4 0.78 0.77 0.76

Example 1 5 0.77 0.76 0.76

Initial output durability Z output voltage (V)

Voltage (V) After 500 hours After 2000 hours

Example 1 0 0.77 0.73 0.68

Example 1 1 0.76 No power generation No power generation

Example 1 2 0.76 0.72 0.66 From the results of the above Examples and Comparative Examples, the open circuit test of high temperature and low humidification,

In the OCV test), hydrogen peroxide or peroxide generated at the anode and at the power source Although the conventional electrolyte membrane was deteriorated due to radicals and the hydrogen leak increased, it is recognized that the electrolyte membrane of the present invention shows remarkably excellent durability.

Industrial applicability

The electrolyte membrane of the present invention has extremely excellent durability against hydrogen peroxide or peroxide radical generated by power generation of a fuel cell. Therefore, the polymer electrolyte fuel cell provided with the membrane electrode assembly having the electrolyte membrane of the present invention is suitable for low-humidification power generation and high-humidification power generation even at high temperatures of 100 ° C or higher.ても But it has long-term durability. This patent application was filed on June 22, 2004, Japanese Patent Application No. 2004-183712, Japanese Patent Application No. 2004-225706, filed on August 2, 2004, filed on September 13, 2004 The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2004-265176 and Japanese Patent Application No. 2005-118412 filed on April 15, 2005 are hereby incorporated by reference. Of the present invention.

Claims

The scope of the claims

[1] An electrolyte membrane for a polymer electrolyte fuel cell, comprising a cation exchange membrane which is a polymer compound having a cation exchange group and containing cerium ion.

[2] A polymer electrolyte fuel cell comprising a polymer compound having a cation exchange group and a cation exchange membrane, wherein a part of the cation exchange group is ion-exchanged with cerium ions. Electrolyte membrane.

[3] A polymer compound comprising a cation exchange membrane in which two or more layers of a polymer compound having a cation exchange group are laminated, wherein at least one of the two or more layers contains cerium ions. Electrolyte membrane for molecular fuel cells.

[4] A polymer compound having a cation exchange group is composed of a cation exchange membrane in which two or more layers are laminated, and at least one of the two or more layers has at least a part of the cation exchange group of cerium. An electrolyte membrane for a polymer electrolyte fuel cell, comprising a cation exchange membrane ion-exchanged by ions.

5. The electrolyte membrane for a solid polymer fuel cell according to claim 1, wherein the polymer compound having a cation exchange group is a polymer compound having a sulfonic acid group.

[6] Cerium ions contain 0.3 to 20% of the number of —SO— groups contained in the cation exchange membrane.

Three

6. The electrolyte membrane for a polymer electrolyte fuel cell according to claim 5, wherein

7. The polymer electrolyte membrane for a polymer electrolyte fuel cell according to claim 5, wherein the polymer compound having a sulfonic acid group is a perfluorocarbon polymer having a sulfonic acid group.

[8] The perfluorocarbon polymer is CF = CF— (OCF CFX) —O— (CF)

2 2 m p 2 n

-SO H perfluorovinyl compound (m represents an integer of 0 to 3, η represents 1 to 12

Three

And ρ represents 0 or 1, and X represents a fluorine atom or a trifluoromethyl group. 9. The electrolyte membrane for a polymer electrolyte fuel cell according to claim 7, which is a copolymer containing a polymerized unit based on the above formula) and a polymerized unit based on tetrafluoroethylene.

[9] The polymer compound having a sulfonic acid group has an aromatic ring in the main chain of the polymer or in the main chain and a side chain, and has a structure in which a sulfonic acid group is introduced into the aromatic ring. 7. The solid fraction according to claim 5, wherein the ion exchange capacity is 0.8 to 3.0 meq. Electrolyte membrane for secondary fuel cells.

[10] The electrolyte membrane for a polymer electrolyte fuel cell according to any one of claims 1 to 9, which is a reinforced electrolyte membrane.

[11] The method for producing an electrolyte membrane according to any one of [1] to [10], wherein the cation exchange membrane, which is a polymer compound having a cation exchange group, is also immersed in an aqueous solution containing cerium ions. A method for producing an electrolyte membrane for a polymer electrolyte fuel cell, comprising:

12. The method for producing an electrolyte membrane according to claim 11, wherein the aqueous solution containing cerium ions is an aqueous cerium nitrate solution or an aqueous cerium sulfate solution.

[13] A membrane electrode assembly for a polymer electrolyte fuel cell, comprising: an anode having a catalyst layer containing a catalyst and an ion exchange resin; a force sword; and an electrolyte membrane disposed between the anode and the force sword. A membrane electrode assembly for a polymer electrolyte fuel cell, wherein the electrolyte membrane is the electrolyte membrane according to any one of claims 1 to 10.

[14] A membrane electrode assembly for a polymer electrolyte fuel cell, comprising: an anode having a catalyst layer containing a catalyst and an ion exchange resin; a force sword; and an electrolyte membrane disposed between the anode and the force sword. The ion-exchange resin contained in at least one of the anode and the force source contains cerium ions, and is a membrane electrode assembly for a polymer electrolyte fuel cell.

15. The membrane / electrode assembly for a polymer electrolyte fuel cell according to claim 13, wherein the ion exchange resin contained in at least one of the anode and the power source contains cerium ions.